This invention relates to an operator adjustable gain control feature for controlling the gain of an ultrasonic scanning system as a function of the scanning angle of a received beam.
Existing ultrasonic scanning systems employ several techniques for controlling transmit or receive channel gains. At least some of these gains are operator adjustable to help present the desired image on the display screen. For example, the Hewlett-Packard SONOS 1000 ultrasound system incorporates an operator adjustable transmit gain control. Varying this control affects the intensity of the entire signal being displayed. Also well known is the Time Gain Compensation (TGC) function, which allows an operator to adjust the receive channel gain in discrete steps as a function of distance from the origin of the beam. The TGC control permits the adjustment of gain to compensate for the attenuation of the ultrasound signal as it propagates through the medium being scanned. Finally, it may be desirable to compensate for the non-uniform signal response of a transducer as a function of the angular position of this ultrasound beam. This is accomplished in a system such as the SONOS 1000 by storing in memory gain compensation values signals which adjust the receive gain at each position of the beam to compensate for this non-uniform response. A set of correction coefficients may be stored for each transducer of a particular type or frequency. These compensation values generally are not operator controllable.